clearer comments about config serialization

dan/ocr/document/train.py

@@ -239,7 +239,10 @@ def get_config():
 
 def serialize_config(config):
     """
-    Serialize a dictionary to transform it into json and remove the credentials
+    Make every field of the configuration JSON-Serializable and remove sensitive information.
+
+    - Classes are transformed using their name attribute
+    - Functions are casted to strings
     """
     # Create a copy of the original config without erase it
     serialized_config = deepcopy(config)
@@ -282,6 +285,7 @@ def serialize_config(config):
         "synthetic_data" in config["dataset_params"]["config"]
         and config["dataset_params"]["config"]["synthetic_data"]
     ):
+        # The Probability scheduler is a function and needs to be casted to string
         serialized_config["dataset_params"]["config"]["synthetic_data"][
             "proba_scheduler_function"
         ] = str(